(a) Field of the Invention
The present invention relates to an apparatus for and a method of automatically producing accompaniment such as bass, chord and arpeggio tones in an electronic musical instrument, and more particularly it pertaines to the apparatus for and the method of the type mentioned above for materializing complicated accompaniment with a relatively small amount of memory data, by storing data representing a plurality of accompaniment segments forming a plurality of mutually different accompaniment patterns of predetermined lengths, and by storing, separately from the above, the orders with which these accompaniment segments are to be aligned sequentially.
(b) Description of the Prior Art
In the past, there has been known an automatic accompaniment apparatus having a keyboard provided with a plurality of keys and being installed in an electronic musical instrument and being designed so that an accompaniment data for one to two bars (measures) are stored, and that these accompaniment data are read out repetitively in accordance with the progression of the keyboard performance while being added with key depression data to thereby generate such tone signals as bass, chord or arpeggio.
According to the above-described prior art, the accompaniment data has a length extending to only one to two bars, and thus the accompaniment has tended to become monotonous. For example, U.S. Pat. No. 4,217,804 discloses an automatic accompaniment apparatus wherein an arpeggio pattern constituting two bars is simply repeated in accompaniment. Examples of an arpeggio pattern are shown in FIGS. 12(a) to 12(c) therein. Similarly, in an electronic musical instrument shown in U.S. Pat. No. 4,282,788 an automatic accompaniment apparatus is disclosed. More precisely, examples of a chord performance rhythm pattern of two bars are disclosed in FIG. 4 therein. In an automatic chord performance, such rhythm pattern is performed repetitively.
In order to materialize a complicated accompaniment performance, therefore, consideration may be made to storing a lengthy sequential train of accompaniment data extending to a number of bars. Such a lengthy train of accompaniment data, however, has led to a substantial increase in the amount of data requiring to be stored.